My solution is to find the file named "script.rpy", and change its suffix to '.txt'. Then you may open it and search the dialogues mentioned in the game, and just replace the dialogues with words in your language. If there are garbled words when you start the game again, you just need to try another font which supports your language.
OK,it can work. Personnaly I created a new renpy project and I add all the game's files. After that, I generated translation files with renpy which find automatically the dialogue texts. After that, you just gave to translate sentence after sentence (unfortunately, it's a little more difficult than that because some sentences are not found by the generation method). And to edit the file I use Atom, which is include in renpy
